[PATCH v3 2/2] pmdomain: imx: Fix i.MX8MP VC8000E power up sequence

[Peng Fan (OSS)]

From: Peng Fan <peng.fan at nxp.com>

Per errata[1]:
ERR050531: VPU_NOC power down handshake may hang during VC8000E/VPUMIX
power up/down cycling.
Description: VC8000E reset de-assertion edge and AXI clock may have a
timing issue.
Workaround: Set bit2 (vc8000e_clk_en) of BLK_CLK_EN_CSR to 0 to gate off
both AXI clock and VC8000E clock sent to VC8000E and AXI clock sent to
VPU_NOC m_v_2 interface during VC8000E power up(VC8000E reset is
de-asserted by HW)

Add a bool variable is_errata_err050531 in
'struct imx8m_blk_ctrl_domain_data' to represent whether the workaround
is needed. If is_errata_err050531 is true, first clear the clk before
powering up gpc, then enable the clk after powering up gpc.

[1] https://www.nxp.com/webapp/Download?colCode=IMX8MP_1P33A

Fixes: a1a5f15f7f6cb ("soc: imx: imx8m-blk-ctrl: add i.MX8MP VPU blk ctrl")
Cc: stable at vger.kernel.org
Signed-off-by: Peng Fan <peng.fan at nxp.com>
---
 drivers/pmdomain/imx/imx8m-blk-ctrl.c | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/drivers/pmdomain/imx/imx8m-blk-ctrl.c b/drivers/pmdomain/imx/imx8m-blk-ctrl.c
index e13a47eeed75d7189aa15370a7bee4cceb05a1d6..1cd0a22ce3e533358dd7449da9989162b36c5fe6 100644
--- a/drivers/pmdomain/imx/imx8m-blk-ctrl.c
+++ b/drivers/pmdomain/imx/imx8m-blk-ctrl.c
@@ -54,6 +54,15 @@ struct imx8m_blk_ctrl_domain_data {
 	 * register.
 	 */
 	u32 mipi_phy_rst_mask;
+
+	/*
+	 * VC8000E reset de-assertion edge and AXI clock may have a timing issue.
+	 * Workaround: Set bit2 (vc8000e_clk_en) of BLK_CLK_EN_CSR to 0 to gate off
+	 * both AXI clock and VC8000E clock sent to VC8000E and AXI clock sent to
+	 * VPU_NOC m_v_2 interface during VC8000E power up(VC8000E reset is
+	 * de-asserted by HW)
+	 */
+	bool is_errata_err050531;
 };
 
 #define DOMAIN_MAX_CLKS 4
@@ -108,7 +117,11 @@ static int imx8m_blk_ctrl_power_on(struct generic_pm_domain *genpd)
 		dev_err(bc->dev, "failed to enable clocks\n");
 		goto bus_put;
 	}
-	regmap_set_bits(bc->regmap, BLK_CLK_EN, data->clk_mask);
+
+	if (data->is_errata_err050531)
+		regmap_clear_bits(bc->regmap, BLK_CLK_EN, data->clk_mask);
+	else
+		regmap_set_bits(bc->regmap, BLK_CLK_EN, data->clk_mask);
 
 	/* power up upstream GPC domain */
 	ret = pm_runtime_get_sync(domain->power_dev);
@@ -117,6 +130,9 @@ static int imx8m_blk_ctrl_power_on(struct generic_pm_domain *genpd)
 		goto clk_disable;
 	}
 
+	if (data->is_errata_err050531)
+		regmap_set_bits(bc->regmap, BLK_CLK_EN, data->clk_mask);
+
 	/* wait for reset to propagate */
 	udelay(5);
 

-- 
2.37.1